Merge branch 'version_output' into develop (PR #1273)

This merge adds a new 'version' global attribute to all netCDF stream output
files.

The value of the attribute is taken from the domain%core%modelVersion variable,
which ultimately comes from the version attribute in a core's Registry.xml file.

Example attributes in an output file, including the new 'version' attribute, are
shown below.

// global attributes:
                :model_name = "mpas" ;
                :core_name = "atmosphere" ;
                :version = "8.2.2" ;
                :source = "MPAS" ;

* version_output:
  Add a new 'version' global attribute to all netCDF stream output files

Author: mgduda

src/driver/mpas_subdriver.F

@@ -512,6 +512,7 @@ subroutine add_stream_attributes(domain)
      
       call MPAS_stream_mgr_add_att(domain % streamManager, 'model_name', domain % core % modelName)
       call MPAS_stream_mgr_add_att(domain % streamManager, 'core_name', domain % core % coreName)
+      call MPAS_stream_mgr_add_att(domain % streamManager, 'version', domain % core % modelVersion)
       call MPAS_stream_mgr_add_att(domain % streamManager, 'source', domain % core % source)
       call MPAS_stream_mgr_add_att(domain % streamManager, 'Conventions', domain % core % Conventions)
       call MPAS_stream_mgr_add_att(domain % streamManager, 'git_version', domain % core % git_version)